documentation

Pull request #2654: Feature/ZBXNEXT-9849 7.2 D

Merge in WEB/documentation from feature/ZBXNEXT-9849-7.2-D to release/7.2

* commit '6d10f73f40c43057888c8ff19fa41ea235d551b9':
  ZBXNEXT-9849 improvements to list style consistency and introductory sentence, deleted repeating command.
  ZBXNEXT-9849 guide improvements.
  ZBXNEXT-9849 removed a sentence, fixed lists formatting.
  ZBXNEXT-9849 addressing recommendations.
  ZBXNEXT-9849 updated a screenshot, corrected identation.
  ZBXNEXT-9849 corrected a comment block.
  ZBXNEXT-9849 moved pictures to correct folder, improved troubleshooting sections, small corrections.
  ZBXNEXT-9849 guide improvements, adding screenshots.
  ZBXNEXT-9849 guide updates.
  ZBXNEXT-9849 added info to the guide.
  ZBXNEXT-9849 initial draft of the guide.